This invention relates in general to gas flow sensors for detecting the flow of gas in a gas conduit, and more specifically involves a very simple, fail-safe, gas flow sensor.
Gas burners, such as gas ranges, are subject to failures and other conditions that render them dangerous. For example, if a burner fails to light or is extinguished by an overflowing pot, continued gas flow may result in an explosion or fire or may suffocate people. Many fires, explosions, and suffocations are attributable each year to gas burners. Therefore, there has been a need for a safety system for a gas range that turns off the gas supply to the range upon detection of a gas leak, absence of a flame, or smoke. Such a safety system requires a fail-safe gas flow sensor.
This invention is a gas flow sensor, generally comprising a housing defining an internal cavity, a diaphragm assembly separating the internal cavity into a first chamber in communication with a gas inlet and a second chamber in communication with a gas outlet and having orifices therethrough for passage of gas, a valve mounted on the diaphragm assembly for closing and opening the orifices; and a sensing unit sensing when the diaphragm assembly has moved at least to a predetermined location.
In an exemplary embodiment, the diaphragm assembly includes a diaphragm having a flexible outer portion and a central piston including a bore therethrough through which a valve stem is mounted. A valve face, connected to the stem within the first chamber, moves between a closed position closing the orifice and piston bore and an open position wherein gas can pass through the orifice, resulting from the stem being pushed against a wall of the second chamber.
The features and advantages of the invention will be readily understood when the detailed description thereof is read in conjunction with the accompanying drawings wherein like reference numerals refer to like parts throughout.